The recent insurgency in Iraq has spawned fresh questions about what interests the Islamic State of Iraq and al-Sham (ISIS) represents and how exactly the organization relates to al-Qaeda. Indeed, although the groups have found tenuous common cause in military engagements such as Iraq, their relations have been characterized by distrust, open competition, and outright hostility. The final break came with ISIS’s recent expansion from Iraq into Syria, spurring al-Qaeda to disavow the group earlier this year. In the battle for global jihadist supremacy, ISIS now holds the upper hand, with al-Qaeda struggling just to fend off its own decline.

In this new Institute Research Note, Aaron Y. Zelin examines the history and evolution of relations between ISIS and al-Qaeda, detailing factors that could help or hinder each group in their battle for domination of the global Jihadi arena.